Application of voltammetry for quantitative analysis of chromium in molten 2LiF-BeF2 (FLiBe) salt

The electrochemical behavior of Cr2+ in molten 2LiF-BeF2 (FLiBe) salt at temperatures between 500 °C and 700 °C was studied using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). LSV has been used to establish a stable reference electrode with the Be/Be2+ couple. The ability to distinguish between common corrosion products, such as Cr2+ and Fe2+, with CV has been demonstrated using the Be/Be2+ reference reaction. Methods for high-precision, in-situ quantitative measurement of Cr2+ concentration are developed. Models for predicting the concentration of Cr2+ and its diffusion coefficient are approximated by relating faradaic cathodic peak current density to Cr2+ concentration at 600 °C and 650 °C. The study provides the basis for the development of a sensor for on-line quantification of corrosion products that improves understanding of materials performance in the molten FLiBe salt.